Patch-clamp amplifiers may be used in cellular and molecular biology to measure and record electrical signals generated by biological tissue. Biological tissue may allow a small current to flow through a cell wall or membrane when the cell is stimulated with a voltage signal. Simply put, patch-clamp amplifiers may be used measure and record a resulting current that flows through a cell as a result of a voltage input. Typically, the voltage input is a step or other function, referred to as a command signal, which may be applied via a pipette that is in contact with the cell. A resulting current may then be measured and recorded.
It can be very difficult to measure and record this resulting cell current. For example, the pipette may have a stray or parasitic capacitance that may generate a large current when the command signal is applied. This large signal may swamp or overwhelm the desired output signal current generated by the cell, thereby making a determination of the actual cell current problematic. Similarly, the pipette and cell may have other stray or parasitic capacitances and resistances and the current signals they produce may similarly hide or mask the current of interest, specifically the current generated by the cell itself.
The solution has been to include various circuits in these patch-clamp amplifiers that compensate for these unwanted signals, thereby leaving the desired signals behind. But this has led to patch-clamp amplifiers having a tremendous complexity. These complex patch-clamp amplifiers have proven to be difficult to manufacture. Further, they have become so specialized that once made, they may be very difficult to reconfigure. For example, it may be desirable to reconfigure one or more circuits in a product update or improvement. The complexity of present patch-clamp amplifiers may limit such reconfiguration.
Moreover, during device use, it may be desirable to quickly reconfigure a patch-clamp amplifier in order to take a set of related measurements. Again, the complexity of present patch-clamp amplifiers may slow the reconfiguration process and limit the ability to take such related measurements.
Thus what is needed are patch-clamp amplifiers that may be readily manufactured, may be simple to reconfigure for product updates, and can be quickly reconfigured into different modes during operation.